The present invention relates to apparatus and methods for evaluating an athlete's initial reaction or starting performance in a contest or practice event.
In a number of athletic competitions such as foot races, all contestants start at a fixed instant, and the performance of each is assessed by the order of crossing the finish line. Typically, in a track event, the runners each first assume a "ready" position on a starting block, and then push off when the start signal, usually an explosion from a starting gun, is given. In some aquatic events related arrangements exist wherein swimmers push off from a wall or release a grip on a support.
For longer track events, where each runner is confined to one lane and the paths curve, it is necessary to have the runners start at different stations which may be placed at staggered positions many meters apart, thus compensating for the incrementally increasing path lengths along the outside lanes. This assures that all runners arrive at a common finish line after running the full, fixed, distance. Because of the spaced-apart starting positions along the track, and because the speed of sound is only about three-hundred fifty meters per second, a delay of up to a tenth of a second is possible between the instant when the starting signal reaches the front starting block and when it reaches the back starting block. This delay can be minimized by appropriate placement of the starting gun to uniformize the distance, hence the sound signal transit time, to the various positions. In addition to this intrinsic spatial delay, each runner has a finite reaction time, typically about one to several tenths of a second, between hearing the sound and pushing off from the starting block. Moreover, the start of a race is a time of extreme nervous tension, and it is not uncommon for a runner to push off early before hearing the starting gun, or even before the gun has been fired.
In general, when such behavior is observed, a false start is called, and all runners must again line up and be prepared to take off. Several false starts may disqualify a runner. However, since the starting activity occurs when contestants are spread out over a number of different starting positions which may further be staggered from each other, and since a false start typically involves time intervals on the order of a small fraction of second, a false start may simply not be observed by the starter or judges, and may go undetected.
There do exist various automated systems which use specialized equipment for detecting false starts by accurately timing when each runner pushes off. Furthermore, some track association rules have codified the definition of a false start as one occurring in less than one hundred milliseconds after the starting signal. This interval corresponds both to the distance between the extreme front and rear starting positions along a standard track, and to a generally accepted minimal reaction time. It also corresponds roughly to the accuracy with which a human observer would be able to discern such a start. Judges may also exercise some discretion in calling a false start.
The general methodology used to detect a false start in the available automated detection systems is to employ a sensor which measures the force exerted by a runner on the starting block, and then to analyze the shape of the force curve to detect a moment which is considered to be the moment when the athlete has pushed off. That moment is then compared to the moment the starting signal was applied to determine whether the athlete's start was too early. The starting signal itself can be provided by an electronic trigger on the starting gun, or by a timing signal derived by detecting the starting shot with a microphone placed close to the gun. The runner's starting moment, determined by a curve analysis algorithm, is typically considered to be a point in time at which the force on the starting block passes a very high threshold, or a moment at which the force peaks. Automated start detection systems of this type generally require modifying the starting blocks, or providing specially configured starting blocks which, instead of transferring all force directly to the track surface, ride on a carriage and are arranged so that all or a portion of the force exerted by the athlete on the starting block is transferred to or through a force sensor, e.g., a strain gauge, which may for example be mounted between the block and the carriage.
One such commercially available system locates the force sensor in a position to detect force exerted in the backward direction, and it analyses the output to determine when the athlete exerts a threshhold force of about 250 Newtons, which is sufficiently high to be accepted as indicative that the athlete has reacted and is pushing off. Such a detection protocol, however, may introduce a certain level of inequality between runners, inasmuch as an athlete with a highly sprung set position normally exerting a force of 240 Newtons will trigger the sensor with a relatively small shift in tension or minor adjustment of his starting posture, whereas another individual who exerts only 100 Newtons in his ready position may be able to initiate more movement without exceeding the false start force threshhold or triggering an alarm. Furthermore, the commercial embodiment of this system requires a track organization to purchase a proprietary set of starting block assemblies.
Another similar system is based on specially modified starting blocks. This system also detects the change in force applied to the starting blocks, but uses a different algorithm to determine the athlete's moment of reaction.
Still another system in current use can be attached to various starting blocks by disassembling the starting block and attaching a special load bearing rear end to the block. In this system, the changes in force are converted to a voltage output which is digitized. As the runner pushes off, the maximum change in force achieved by the athlete is determined, and the moment of reaction, or actual starting time, is taken to be the instant when the curve reaches a threshold percentage, such as twenty per cent, of the maximum value.
Each of the foregoing approaches requires either a special proprietary starting block arrangement in which the block and force sensor are carried on a special carriage or otherwise formed of several components to house the strain detection structure, or else requires an invasive fitting to the preexisting starting block which involves disassembly of the block and attachment of special load bearing rear end to the block. Thus, to use one of the foregoing reaction-time measurement systems, one must either replace existing equipment or extensively customize it. These requirements impose a rather high capital requirement for updating a track system to reliably detect false starts, and conversely, they unduly limit an organization's ability to switch or replace starting block equipment once it has been acquired.
In general, the moment of starting is an important moment. The reaction time of one to several tenths of a second is a relatively large interval, which, for a short distance event, is comparable to the spread between a winning time and a time which does not even place. It is therefore important for an athlete to adopt a position which allows him to leave the block with the greatest possible speed, and to perfect his starting technique so that this is dependably achieved with the smallest reaction time and without false starts. However, practicing one's starting technique involves a cumbersome sequence of acts, and typically involves close observation by a coach. Thus, unlike many aspects of an athlete's performance, the starting reaction cannot be drilled in solitary practice. While an athlete's start may be objectively measured during an actual contest by the above-described systems, such equipment is itself too unwieldy for individual training and casual use by an athlete to improve his reaction time, and it also requires a monitor or operator.
It would therefore be desirable to provide a reaction time detection system which is simply applied to diverse existing starting blocks.
It would also be desirable to provide a reaction time detection system which sets up simply and dependably in a multiple-contestant system.
It would also be desirable to provide a reaction time detection system useful for individual training.
It would be further desirable to provide a reaction time detection system with enhanced warning, alarm, or signaling abilities.
It would further be desirable to provide a reaction time detection system which is automated to make false start determinations and interface with recording or display equipment of the host organization.